Proboscis: The rudimentary organ of an elephant which serves him in place
of the knife-and-fork that Evolution has as yet denied him. For purposes
of humor it is popularly called a trunk.
-- Ambrose Bierce

Q: How do you shoot a blue elephant?
A: With a blue-elephant gun.

Q: How do you shoot a pink elephant?
A: Twist its trunk until it turns blue, then shoot it with
a blue-elephant gun.

Lawrence Radiation Laboratory keeps all its data in an old gray trunk.